A need has been developed for a waste collection vehicle which readily differentiates fibrous combustible materials from non fibrous materials. Many such vehicles have been developed and one of them is described in U.S. Pat. No. 5,122,025 June 1992 by Glomski, a patent which describes a mobile interior wall which opens and closes storage space in a truck. Glomski utilizes small buckets and repeated compaction in the loading zone, which is not practical for loading. The art also discloses a German patent DE 3,231,002 10 Mar. 1983 by Fahrzengbau, which discloses a compressible volume defined by the location of a deflector of a hopper; the location of the hopper cannot be modified by the operator nor can be modified the area of loading. This method although effective in use is very complicated in its mechanical structure.